Along with the development of the Long Term Evolution (LIE) technologies, if an operator can provide a group communication function using the LIE system, then no 2/3G networks will be maintained at all due to the development of the LTE system so that the networks can transition smoothly to the LIE system. For the LTE system, an end to end delay in group communication is required to be no more than 300 ms, and in order to satisfy this required delay, the majority of the enterprises currently tend to reuse the Multimedia Broadcast Multicast Service (MBMS) architecture as a network architecture, and to make some modification to the existing MBMS network architecture so as to satisfy the required delay.
The names of primary nodes and the functions of primary interfaces in the MBMS network architecture of the LTE system will be listed below:
Logic Entities:                Mobility Management Entity (MME);        MBMS Gateway (MBMS GW);        Multi-cell/multicast Coordination Entity (MCE); and        Evolved Node B (eNB); and        
Interfaces:                M3: the interface provides session management related function between the MME and the MCE, e.g., session start notification, and session stop notification;        M2: the interface provides session management, transfer of MBMS scheduling information, and other functions between the MCE and the eNB; and        M1: the interface provides MBMS service transfer between the MBMS GW and the eNB.        
Although the idea of group communication based upon the MBMS network architecture has been proposed at present, there has been absent in the prior art a particular solution to group communication based upon the MBMS network architecture.